Power regulator



" Filed June 27, 1946 I 4 INVENTOR. Watt; mziel fimclyestnr BY .attumegPatented Mar. 23 1948 UNITED STATES PATENT OFFICE POWER REGULATORNathaniel Rochester, Milton, Mass, assignor to Sylvania ElectricProducts 1110., Salem, Mass, a corporation of Massachusetts ApplicationJune 27, 1946, Serial No. 679,841

4 Claims. l.

This invention relates to means for regulating the temperature of thecathode heater in an electronic device and particularly to such meansacting automatically to regulate such temperature within small limits.

An object of the invention is to provide means for maintaining stablecathode emission conditions within an electronic device.

A further object of the invention is to provide means to regulate theemission of the cathode of an electronic tube by utilizing the thermalemission characteristics of a cathode in a control tube which mayotherwise be non-functional with respect to the circuit containing theregulated tube.

A further object of the invention is to provide means for removing thesource of power from the cathode Within a cathode emission regulatedtube when the regulating means fails.

Qther objects and features of the invention will more fully appear fromthe following description and will be particularly pointed out in theclaims.

The present invention involves the use of an auxiliary control tube toregulate the cathode emission of one or more other electronic tubeswhich are employed in any apparatus requiring such tubes for itsoperation. The tube or tubes to be regulated desirably are of theindirectly heated cathode type having a heater element, thermally butnot electrically, connected to the cathode. However, other types ofcathodes having a relatively slow thermal response may be regulated.

The control tube is provided with a cathode which has a relatively rapidthermal response and may be a simple diode tube. The cathode of thecontrol tube is connected to and receives power from the source ofcurrent which supplies power to the cathode or heater of the tube to beregulated. The plate circuit of the control tube is supplied with powerand has connected therein a normally closed relay switch for operationby power conducted by and through the control tube. The switch contactsof the relay are connected to open and close the power circuit to thetwo cathodes.

When the power is turned on the cathodes heat up and since the controltube cathode has a more rapid thermal response it becomes emissive andtherefore conductive before the other cathode. The relay is thusactuated to open the main power supply circuit. The control tube cathodethen starts to cool to non-emissive temperature at which time the relayswitch closes to start another heating cycle.

Repeated heating cycles maintain the cathode of the regulated tube at adesired temperature determined by the thermal emission characteristicsof the control tube cathode.

To provide a better understanding of the invention preferred embodimentsthereof will now be described. Such embodiments are illustrated in thedrawings in which Figure 1 is a diagrammatic View of a basic form of theinvention, and Figure 2 is a diagrammatic view of a different form ofthe invention.

It is of great practical advantage in many applications of theelectronic tube or other electronic device, to maintain the electronicemission of the cathodes of such devices constantly within close limits.The present invention provides a highly effective means foraccomplishing such a result.

The thermionic tube l is the electronic device to be regulated. Thistube may be of any type and is shown herein as a diode having a plate 2,a cathode 3 and a heater element 4. The tube 8 may be incorporated inany desired circuit and since its function therein constitutes no partof the invention no circuit therefore is shown.

Power to energize the heater 4 is derived from. any suitable source suchas a transformer 5 which in turn is connected to a primary power source.The heater 4 is connected to the transformer 5 by the leads 6. A cathode'1 within the control tube 8 is also connected to the leads 5. Ifdesirable or necessary a compensating resistor 9 may be inserted in oneof the leads to the cathode l.

The control tube 8 may be of any suitable type but should have a cathodehaving a thermal response substantially shorter than the cathode of thetube to be controlled. As shown herein the tube 8 is a diode having itsplate I0 connected to a suitable source of direct current or othersource of power and has connected in its plate lead II the magnet l3 ofrelay switch [2. The switch contacts M of the relay are connected in oneof the leads 6 where they function to turn on and off the supply ofpower to the cathodes 3 and l. The relay is adjusted to normally closethe power circuit to the tube cathodes.

When the power is turned on to the cathodes and plate Ill the heater 4and the cathode 1 start to heat up. Because of the relatively rapidresponse of the cathode I it becomes electron-emissive soon after thepower is turned on. As soon as the control tube becomes'conducting therelay l2 acts to cut off the power to the cathodes which start to cool.The cathode I again being the more responsive element quickly cools tothe non-conducting temperature at which time the relay 3 r turns on thepower to the cathodes and the heating cycle is repeated. After a fewsuch cycles the cathode 3 reaches its operating temperature which ismaintained at the desired level by the thermalemission characteristicsof the cathode 1.

Another form of the invention is shown in Figure 2 in which the emissionof -.a cathode within a-tube 1'6 isregulated by a diode control tube I!and a relay switch [8. This form of the device functions in a mannersimilar to the form shown in Figure 1 but in addition is provided withmeans to automatically out off thepower supply in case of failure of-thecontrol tube .or the control circuit. Thus .the "cathode i5 will notbecome damaged by an uncontrolledflow of power.

The power to energize the cathodes and the control elements may beobtained in any suitable manner. As shownsuch power is obtained from atransformer 19 whoseprimary is connected to a suitable-power-source. Asecondary winding 20 is connected to th'e'c'athodefl'l'inthe tube 11 andthe heater 22-forthecontrolled-cathode l5. Desirably'in" this .t'ormpftheinvention the cathode 2| and heater 22 are=conneoted in series.

The plate '23"of=tub'e ll is supplied with power from -a secondarywinding --on the transformer l9. Connected inserieswith the plate 23 isthe winding 24 of the relay l8 and'the winding 25 ofa,protectorrelay-26. Therelay 24 is adjusted to normallymaintain its oontacts 21,in the line 7 leading to the cathode 2| and heater 22 closed,

in'the same mannerasthe controlrela-y in the other form .of theinvention. The contacts 28 of the relay '26 are connected in the lineleading to the heater 22 and are held closed while the relay =26'isenergized.

,Desirablya variable resistance or reactance 29 may beconnected inparallel with the cathode 2| to provide'for adj ustm'ent-whichmay benecessary to properly maintain correct operating "conditions at thecathode-2| and heater'22-and to provide flexibility in the *apparatustoadapt it to controlemission'in-difierent tubes or otherelectronicdevices.

The winding :25of the relay "26'contains more ampere turns than thatofthe winding 24 on the relay ill. The relay -26 therefore responds tosmaller current -fiow than-relay 18. When power is turnedon to energizewt-he apparatus the oath- 4 tube I1. The initial relatively smallcurrent which flows in the plate circuit actuates the relativelysensitive relay 26 to close the circuit to the heater 22.

As the cathode 2 l becomes more electron emissive the on ofi cycle ofthe relay I8 is started. However, the circuit is so'designed that thecathode -2| remains suificientlvemi'ssive during the cool portion of itscycle to energize the winding 25 and thus keep the switch contacts 28continuously closed.

'Ii 'thetube I! should fail or any portion of the "relay controlcircllitjshould fail the switch contact's' wouldbpen'iand the winding 25would becoineeompletely deenergized at which time the contact 28wouldopen thus cutting offrpower to the heater2'2 within the regulatedtube I 6. The

tube'lit and its associated apparatus is thus protected from possibledamage or malfunction;

Any suitable -means may be employed to;main tain the contacts'28 on therelay 26 closed during atleast one on-off cycle ofthe relay it. Anothermeans 'for accomplishing thisis shown diagrammatically in Figure 3wherein th'e heater 22 associated with the cathode 15is-suppli-ed'with-power during normal operation of the apparatus but isdisconnected from the power source when the control tube orany part =-ofthecontroi circuit fails.

the heater 22.

to slow down its motionsuchas the dashpot-t'!diagrammaticallyillustrated. The dash potmay be hydraulic or pneumaticinoperation.

The dash-pot31 may be'construc ted to permit the member 35 to movereadily into contacting position. Therefore when the apparatus isstarted and the winding 34 is energized the contactor 35 will close the.circuitto the heater '22.

ode-2l h'eatsup and flow of current begins to-build up withinthe-tube H.The relativelysmallcurrent which first appears actuates the relay 26first to turnon the power 'to the heater22. Subsequently the 'relay I8willact-to cut ofi power to both the-cathode-ZI and-heater 22. Thecathode 2! will start to'cool down until the winding 24 permits theswitch contacts 21 -toagain turn on the power. -A-continuous seriesofcycles is thus maintainedas-in thedevice of Figure -1.

In the latter *formiof the invention there are additional events whichtake place involving additional elements asfollows. The-relay 26 isprovided with an additional contact til to which is connected ashuntingresistance '31 which :in turn is connected to opposite sides of the lineleadin to the heater 22.

When the-apparatus has been cutoutof service the movable-contaot of therelay 26 rests upon thecontact 38. Thus when-the power is turned on nocurrent fiows to the heater 22. A circuit does however exist through thecathode 2!; the

resistor 31 and winding 28. The current flowing in this circuitstarts to-heat the cathode 2! which causes current to flow in the plate circuitof the The contacts are so adjusted that it requires-a substantialmovement of themember 35 to open the circuit. In operation therefore the011* 0fi cycles of the control relay willnot 'openthe circuit tothe-heater-22because successive attempts of the spring 3ito open thecircuit will be cancelled by the resistance of the dash pot. A con- 7tinuously closed circuitto the heater 2 2 will exist therefore until thecontrol tube or circuit fails.

What I claim is: t 1. Apparatus for regulatin g cathode emissioncomprising a cathode to be regulated situated within an electronicdevice, a-control tube having at least a plate and cathode, power supplywithin an electronic device, a control tube having at least a cathodeanda plate, said-latter cathode being more critically dependent ontemperature and having a faster thermal response than the regulatedcathode, a source of power, conductors connecting said power source toboth cathodes, a source of power for said control tube plate, circuitconnections from said latter power source to said plate, a relay switchhaving an electromagnet connected to be energized by said plate circuitand switch contacts connected to turn on and off the power to saidcathodes and means to close said switch when the said electromagnet isdeenergized whereby the regulated cathode receives successive charges ofcurrent metered by the thermal emission characteristics of the controltube cathode.

3. Apparatus for regulating cathode emission comprising a cathode to beregulated, situated within an electronic device, a control tube havingat least a plate and cathode, power supply means for energizing bothcathodes and the plate, a control relay switch and a cut-out relayswitch connected to receive actuating current from said control tube,said cut-out relay being constructed to respond to a substantiallysmaller current flow than said control relay, the switching means onsaid cut-out relay being operable while the relay is energized toconduct current to the regulated cathode and when deenergized to cut offsuch current, the switching means on the control relay acting to turn onand ofi the power to the cathodes as the control tube becomesrespectively partially conducting and conducting, the electrical andthermal characteristics of the control system being such that thecontrol tube will be continuously at least partially conducting tomaintain the cut off relay energized, whereby the regulated cathodereceives current metered by the thermal emission characteristics of thecontrol 6 tube cathode and will have its power cut ofi if the controltube or circuit fails.

4. Apparatus for regulating cathode emission comprising a cathode to beregulated situated Within an electronic device, a control tube having atleast a plate and a cathode the latter cathode having a faster thermalemission response than the regulated cathode, power supply means forenergizing both cathodes and said plate, a control relay switch and acut-out relay switch connected to receive actuating current from saidcontrol tube, said out out switch having contact members operating whenthe switch is energized to close the power supply line to said regulatedcathode, delaying means connected to said contact members acting whenthe switch is deenergized to maintain closed said contacts for asubstantial period of time after it is deenergized, contact elements onsaid control relay acting to turn on and off the power to both cathodesrespectively as the control tube becomes non-conductive and conductiveat a rate faster than the cycle of operation of said delaying meanswhereby the regulated cathode is fed successive charges of currentmetered by the thermal emissive characteristics of the control tubecathode and will have its power cut 01f if the control tube or circuitfails.

NATHANIEL ROCHESTER.

REFERENCES CITED UNITED STATES PATENTS Name Date Peters Aug. 20, 1940Number

